U.S. Pat. No. 6,605,775 to Seeber et al. issued Aug. 12, 2003 with the title “Floating radio frequency trap for shield currents” and is incorporated herein by reference. In U.S. Pat. No. 6,605,775, Seeber et al. describe a floating shield current trap that provides first and second concentric tubular conductors electrically connected to provide a resonance-induced high impedance of current flow in a path consisting of the inner and outer conductors and their junctions thereby suppressing coupled current flow on a shield of a conductor contained within the first inner tubular conductor.
U.S. Pat. No. 6,664,465 to Seeber issued Dec. 16, 2003 with the title “Tuning system for floating radio frequency trap” and is incorporated herein by reference. In U.S. Pat. No. 6,664,465, Seeber describes a floating shield current trap provides two resonance loops formed of split concentric tubular conductors joined radially at their axial ends. Adjustment of the separation of these loops provides a change in coupling between the loops effecting a simplified tuning of the resonance of the trap for different expected frequencies of interfering shield current.
U.S. Pat. No. 6,593,744 to Burl et al. issued Jul. 15, 2003 with the title “Multi-channel RF cable trap for magnetic resonance apparatus” and is incorporated herein by reference. In U.S. Pat. No. 6,593,744, Burl et al. describe a multi-channel RF cable trap that blocks stray RF current from flowing on shield conductors of coaxial RF cables of a magnetic resonance apparatus. An inductor is formed by a curved semi-rigid trough constructed of an insulating material coated with an electrically conducting layer. Preferably, the inductor and the cable follow an “S”-shaped path to facilitate good electromagnetic coupling. The RF cables are laid in the trough and the shield conductors inductively couple with the inductor. A capacitor and optional trim capacitor are connected across the trough of the inductor to form a resonant LC circuit tuned to the resonance frequency. The LC circuit inductively couples with the shield conductors to present a signal-attenuating high impedance at the resonance frequency. The resonant circuit is preferably contained in an RF-shielding box with removable lid.
Low-power circuits can use varactors (electrically variable capacitors), field-effect transistors (used as variable gain elements or variable resistors) and like components that are directly electrically-adjustable, for use in adjusting frequency, impedance or other circuit characteristics and parameters, however such components are often unsuitable or inoperative in high fields.
U.S. Pat. No. 6,495,069 issued Dec. 17, 2002 to Lussey et al. with the title “Polymer composition” and is incorporated herein by reference. In U.S. Pat. No. 6,495,069, Lussey et al. describe a polymer composition comprises at least one substantially non-conductive polymer and at least one electrically conductive filler and in the form of granules. Their elastomer material was proposed for devices for controlling or switching electric current, to avoid or limit disadvantages such as the generation of transients and sparks which are associated with the actuation of conventional mechanical switches. They described an electrical conductor composite providing conduction when subjected to mechanical stress or electrostatic charge but electrically insulating when quiescent comprising a granular composition each granule of which comprises at least one substantially non-conductive polymer and at least one electrically conductive filler and is electrically insulating when quiescent but conductive when subjected to mechanical stress. They did not propose a means for electrically activating such switches.
U.S. Pat. No. 8,299,681 to Snyder, Vaughan and Lemaire issued Oct. 30, 2012 with the title “Remotely adjustable reactive and resistive electrical elements and method” and is incorporated herein by reference. In U.S. Pat. No. 8,299,681, Snyder, Vaughan and Lemaire describe an apparatus and method that includes providing a variable-parameter electrical component in a high-field environment and based on an electrical signal, automatically moving a movable portion of the electrical component in relation to another portion of the electrical component to vary at least one of its parameters. In some embodiments, the moving uses a mechanical movement device (e.g., a linear positioner, rotary motor, or pump). In some embodiments of the method, the electrical component has a variable inductance, capacitance, and/or resistance. Some embodiments include using a computer that controls the moving of the movable portion of the electrical component in order to vary an electrical parameter of the electrical component. Some embodiments include using a feedback signal to provide feedback control in order to adjust and/or maintain the electrical parameter. Some embodiments include a non-magnetic positioner connected to an electrical component configured to have its RLC parameters varied by the positioner.
U.S. Patent Application Publication No. 2010/0253348 by Wiggins published Oct. 7, 2010 with the title “Radio Frequency Coil Arrangement for High Field Magnetic Resonance Imaging with Optimized Transmit and Receive Efficiency for a Specified Region of Interest, and Related System and Method,” and is incorporated herein by reference. In the application 2010/0253348, Wiggins describes exemplary embodiments of a coil arrangement that can include, e.g., a plurality of elements which can be provided at an angle from one another. The angle can be selected to effectuate an imaging of a target region of interest at least one of a predetermined depth or range of depths, for example. In certain exemplary embodiments according to the present disclosure, the angle can be selected to effectuate an exemplary predetermined transmit efficiency for at least one of the elements. Additionally, the exemplary angle can be selected to effectuate a predetermined receive sensitivity for at least one of the elements. Further, according to certain exemplary embodiments of a coil arrangement in according to the present disclosure, the angle can be adjusted manually and/or automatically.
A journal article, “96-Channel Receive-Only Head Coil for 3 Tesla: Design Optimization and Evaluation” by Graham C. Wiggins et al. (Magn. Reson. Med. 2009 September; 62(3): 754-762. doi:10.1002/mrm.22028) describes a receive coil, and is incorporated herein by reference.
U.S. Pat. No. 4,885,539 to Roemer et al. issued Dec. 5, 1989 with the title “Volume NMR coil for optimum signal-to-noise ratio” and is incorporated herein by reference. In U.S. Pat. No. 4,885,539, Roemer et al. describe an RF volume coil with optimized signal-to-noise ratio, for NMR use, has a reduced length Lc, which is between about 0.3rs and about 1.5rs, where rs is the radius of a sample-to-be-investigated, contained within the cylindrical volume coil, with the volume coil radius rc being between about 1.0rs and about 1.6rs the “short” volume coil has an improved SNR for a voxel located substantially on the central plane of the coil, relative to the SNR of a “normal”-length volume coil with Lc greater or equal to 4rs.
A journal article, “The NMR Phased Array” by P. B. Roemer et al. (Magn. Reson. Med. 1990 November; Vol. 16 Issue 262 pages 192-225) describes a phased array receive coil, and is incorporated herein by reference. Roemer et al. describe ways to overlap coil loops (circular loops overlapped by spacing the centers of the circular loops at 0.75 diameter, and square loops by about 0.9 diameter; and the loops are all the same size) to reduce mutual-induction interference.
U.S. Pat. No. 6,534,983 to Boskamp et al. issued Mar. 18, 2003 with the title “Multi-channel phased array coils having minimum mutual inductance for magnetic resonance systems” and is incorporated herein by reference. In U.S. Pat. No. 6,534,983, Boskamp et al. describe a multi-channel phased array coil for use in a magnetic resonance (MR) system is disclosed herein. The phased array coil includes N coils configured in an array, each of the N coils having a geometric shape and overlapping with (N−1) coils to form an overlap area within the array. The geometric shape of each of the coils and the overlap area are configured to cause a mutual inductance between every pair of the coils to be less than 10 percent of the self-inductance of each of the N coils. At least four coils are provided in the phased array coil.
U.S. Pat. No. 6,538,441 issued to Watkins et al. on Mar. 25, 2003 with the title “RF coil for reduced electric field exposure for use in very high field magnetic resonance imaging” and is incorporated herein by reference. In U.S. Pat. No. 6,538,441, Watkins et al. describe an RF coil assembly for a very high field Magnetic Resonance Imaging (MRI) system is provided. The RF coil assembly comprises a plurality of conductors arranged cylindrically and disposed about a patient bore tube of the MRI system. Each of the conductors is configured for the RF coil assembly to resonate at substantially high frequencies. Further, the RF coil assembly comprises a plurality of capacitive elements disposed between and connecting respective ends of the conductors and further disposed in a spaced-apart relationship with the patient bore tube. The capacitive elements are for electrically interconnecting the plurality of conductors at the respective ends of the conductors.
U.S. Pat. No. 6,822,448 issued to Watkins et al. on Nov. 23, 2004 with the title “RF coil for very high field magnetic resonance” and is incorporated herein by reference. In U.S. Pat. No. 6,822,448, Watkins et al. describe an RF coil assembly for a very high field Magnetic Resonance Imaging (MRI) system is provided comprising a plurality of conductors arranged cylindrically and disposed about a cylindrical patient bore tube of the MRI system and a plurality of capacitive elements for electrically interconnecting the plurality of conductors at respective ends of the conductors. The conductors have a width selected for the RF coil assembly to resonate at substantially high frequencies. A very high field Magnetic Resonance Imaging (MRI) system is provided that comprises a RF coil assembly adapted to resonate at substantially high frequencies, a RF coil shield assembly and a plurality of RF drive power cables.
U.S. Patent Application Publication 2007/0236490 of Casteele et al. published on Oct. 11, 2007 with the title “Medical image display and review system” and is incorporated herein by reference. This publication 2007/0236490 describes an image display and review system for display of medical images represented by a digital image data set wherein a pre-defined number of viewports for display of different image representations is provided and wherein at least some of these viewports are configured to enable sequential display of different image representations deduced from the digital image data set.
U.S. Patent Application Publication 2013/0106416 of Morich et al. published on May 2, 2013 with the title “Router and coil array for ultra high field MRI”, and is incorporated herein by reference. This publication 2013/0106416 describes a router for use with magnetic resonance systems that selectively routes unique excitation signals generated by a multi-channel radio-frequency (RF) amplifier over transmission lines (Tx) to any one of a plurality of connection panels which each accepts at least one RF coil assembly having multiple coil elements. Each connection panel includes transceiver ports for connecting at least one conductor of the coil elements to a corresponding transceiver channel (T/R). The router selectively routes magnetic resonance signals received by the conductors from the transceiver channels (T/R) to a multi-channel RF receiver. The “coin” (coil) elements may carry sine-mode currents or uniform currents.
U.S. Pat. No. 8,854,042 by Vaughan and Lemaire titled “Method and coils for human whole-body imaging at 7 T,” issued Oct. 7, 2014 and claims priority benefit, under 35 U.S.C. § 119(e), of U.S. Provisional Patent Application No. 61/371,170, filed on Aug. 5, 2010 and titled “Coils for human whole-body imaging at 7T,” each of which is incorporated herein by reference in its entirety. A progressive series of five new coils is described. The first coil solves problems of transmit-field inefficiency and inhomogeneity for heart and body imaging, with a close-fitting, 16-channel TEM conformal array design with efficient shield-capacitance decoupling. The second coil progresses directly from the first with automatic tuning and matching, an innovation of huge importance for multi-channel transmit coils. The third coil combines the second, auto-tuned multi-channel transmitter with a 32-channel receiver for best transmit-efficiency, control, receive-sensitivity and parallel-imaging performance. The final two coils extend the innovative technology of the first three coils to multi-nuclear (31P-1H) designs to make practical human-cardiac imaging and spectroscopy possible for the first time at 7 T.
U.S. Pat. No. 8,217,653 by Vaughan issued Jul. 10, 2012, titled “Multi-channel RF coil system with multi-channel RF coil transceiver detecting more than one frequency at the same time for magnetic resonance imaging systems and methods,” and is incorporated herein by reference. This U.S. Pat. No. 8,217,653 describes an RF coil system for magnetic resonance applications that includes a multi-channel RF coil transceiver and a multi-channel RF coil. The RF coil system is structured for reconfiguration among a plurality of operational modes.
U.S. Pat. No. 8,193,809 by Akgun et al. issued Jun. 5, 2012 with the title “Three dimensional RF coil structures for field profiling” and is incorporated herein by reference. This U.S. Pat. No. 8,193,809 describes a radio frequency (RF) that include a plurality of transmission line elements, wherein at least one of the plurality of transmission line elements may have at least one dimension different than a dimension of another one of the plurality of transmission line elements. In some cases, each of the transmission line elements may include a signal line conductor and a ground plane conductor separated by a dielectric.
U.S. Pat. No. 8,380,266 by Vaughan et al. issued Feb. 19, 2013 with the title “Coil element decoupling for MRI” and is incorporated herein by reference. This U.S. Pat. No. 8,380,266 describes an RF coil adjacent an imaging region includes a plurality of conducting coil elements, with each conducting coil element including a proximal portion and a distal portion. The RF coil also includes a capacitance between the distal portions of the at least two conducting coil elements. A mutual coupling inductance between at least two conducting coil elements of the plurality of conducting coil elements is substantially cancelled by the capacitance between the distal portions of the at least two conducting coil elements.
U.S. Pat. No. 7,268,554 issued to Vaughan on Sep. 11, 2007, titled “RF coil for imaging system,” is incorporated herein by reference. In this U.S. Pat. No. 7,268,554, an RF coil suitable for use in imaging systems is described, which coil has a dielectric filled cavity formed by a surrounding conducting enclosure, the conducting enclosure preferably being patterned to form continuous electrical paths around the cavity, each of which paths may be tuned to a selected resonant frequency. The patterning breaks up any currents induced in the coil and shortens path lengths to permit higher frequency, and thus higher field strength operation. The invention also includes improved mechanisms for tuning the resonant frequency of the paths, for selectively detuning the paths, for applying signal to the coil, for shortening the length of the coil and for controlling the field profile of the coil and the delivery of field to the object to the image.
U.S. Pat. No. 6,633,161 issued to Vaughan, Jr. on Oct. 14, 2003, titled “RF coil for imaging system,” is incorporated herein by reference. In this U.S. Pat. No. 6,633,161, an RF coil suitable for use in imaging systems is provided which coil has a dielectric filled cavity formed by a surrounding conducting enclosure, the conducting enclosure preferably being patterned to form continuous electrical paths around the cavity, each of which paths may be tuned to a selected resonant frequency. The patterning breaks up any currents induced in the coil and shortens path lengths to permit higher frequency, and thus higher field strength operation. The invention also includes improved mechanisms for tuning the resonant frequency of the paths, for selectively detuning the paths, for applying signal to the coil, for shortening the length of the coil and for controlling the field profile of the coil and the delivery of field to the object to the image.
U.S. Pat. No. 5,557,247 issued to Vaughan, Jr. on Sep. 17, 1996, titled “Radio frequency volume coils for imaging and spectroscopy,” is incorporated herein by reference. This U.S. Pat. No. 5,557,247 describes a distributed impedance circuit MR coil design comprised of a transmission line tunable cavity resonator which is well suited for but not limited to use at high frequencies and for large volumes such as in high field (e.g., 4.1 Tesla) clinical MR applications. The distributed circuit transmission line resonator is designed for high frequency, large conductive volume applications where conventional lumped element coil designs fail. A resonant coaxial cavity is variably tuned to the Larmor frequency of interest by tunable transmission line elements. The resonator is effective for large head and body sized volumes, high efficiencies, and broad tuning ranges to frequencies of 500 MHz. The B1 homogeneity of the resonator is a function of the electromagnetic properties of the load itself. Maxwell's equations for the fully time-dependent B1 field predicts “coil” homogeneity with finite-element models of anatomic structure. Coil design and construction, and methods of quadrature driving and double tuning the transmission line resonator, are set forth.
U.S. Pat. No. 5,744,957 issued to Vaughan, Jr. on Apr. 28, 1998, titled “Cavity resonator for NMR systems,” is incorporated herein by reference. In this U.S. Pat. No. 5,744,957, a cavity resonator is disclosed for use in nuclear magnetic resonance (NMR) systems. The resonator has a housing defining a cavity having a selected length and cross-sectional shape. A layer of electrically conductive material is provided around at least a portion of the housing enclosing a dielectric material (air, gasses, Teflon®, etc.) and the cavity is energized at a Larmor radio frequency useful for NMR systems. The cavity, i.e., a volume enclosed by conductive walls, furthermore, is dimensioned to resonate at the selected radio frequency to thereby generate an alternating magnetic field through the cavity. An opening in the housing is adapted to be placed adjacent an object to be analyzed.
U.S. Pat. No. 5,886,596 issued to Vaughan, Jr. on Mar. 23, 1999, titled “Radio frequency volume coils for imaging and spectroscopy,” is incorporated herein by reference. This U.S. Pat. No. 5,886,596 describes an electromagnetic shield for an NMR radio frequency coil designed to resonate at a selected Larmor frequency. The shield includes an electrically conductive layer surrounding the coil. This electrically conductive layer has a thickness substantially the same as one skin depth at the selected Larmor frequency. As such, the conductive layer efficiently conducts radio frequency currents at the selected Larmor frequency thereby conducting and containing the radio frequency coils at the selected Larmor frequency within the coil. Simultaneously, an electrically conductive layer, due to its thinness, very inefficiently conducts eddy currents of the type induced by the lower frequency DC gradient current switching transients the gradients are utilized to magnetically localize an image slice or volume. Consequently, the conductive layer simultaneously attenuates low frequency eddy current propagation of the type induced by the switching field gradient currents in the NMR application, and therefore does not substantially shield or affect the gradient fields across the coil.
U.S. Pat. No. 7,800,368 issued to Vaughan, et al. on Sep. 21, 2010, titled “High field magnetic resonance,” is incorporated herein by reference. In this U.S. Pat. No. 7,800,368, a magnetic resonance system is disclosed. The system includes a transceiver having a multichannel receiver and a multichannel transmitter, where each channel of the transmitter is configured for independent selection of frequency, phase, time, space, and magnitude, and each channel of the receiver is configured for independent selection of space, time, frequency, phase and gain. The system also includes a magnetic resonance coil having a plurality of current elements, with each element coupled in one to one relation with a channel of the receiver and a channel of the transmitter. The system further includes a processor coupled to the transceiver, such that the processor is configured to execute instructions to control a current in each element and to perform a non-linear algorithm to shim the coil.
U.S. Pat. No. 6,788,056 issued to Vaughan, et al. on Sep. 7, 2004, titled “Radio frequency magnetic field unit with aperature [sic],” and is incorporated herein by reference. In this U.S. Pat. No. 6,788,056, Vaughan et al. describe an apparatus comprises a radio frequency magnetic field unit to generate a desired magnetic field. In one embodiment, the radio frequency magnetic field unit includes a first aperture that is substantially unobstructed and a second aperture contiguous to the first aperture. In an alternative embodiment, the radio frequency magnetic field unit includes a first side aperture, a second side aperture and one or more end apertures. In one embodiment of a method, a current element is removed from a radio frequency magnetic field unit to form a magnetic field unit having an aperture. In an alternative embodiment, two current elements located opposite from one another in a radio frequency magnetic field unit are removed to form a magnetic field unit having a first side aperture and a second side aperture.
U.S. Pat. No. 6,958,607 issued to Vaughan, et al. on Oct. 25, 2005, titled “Assymetric [sic] radio frequency transmission line array,” is incorporated herein by reference. In this U.S. Pat. No. 6,958,607, Vaughan et al. describe an apparatus comprises a radio frequency magnetic field unit to generate a desired magnetic field. In one embodiment, the radio frequency magnetic field unit includes a first aperture that is substantially unobstructed and a second aperture contiguous to the first aperture. In an alternative embodiment, the radio frequency magnetic field unit includes a first side aperture, a second side aperture and one or more end apertures. In one embodiment of a method, a current element is removed from a radio frequency magnetic field unit to form a magnetic field unit having an aperture. In an alternative embodiment, two current elements located opposite from one another in a radio frequency magnetic field unit are removed to form a magnetic field unit having a first side aperture and a second side aperture.
U.S. Pat. No. 7,023,209 issued to Zhang, et al. on Apr. 4, 2006 titled “Method and apparatus for magnetic resonance imaging and spectroscopy using microstrip transmission line coils,” and is incorporated herein by reference. In this U.S. Pat. No. 7,023,209, Zhang et al. describe an apparatus and method for MRI imaging using a coil constructed of microstrip transmission line (MTL coil) are disclosed. In one method, a target is positioned to be imaged within the field of a main magnetic field of a magnet resonance imaging (MRI) system, a MTL coil is positioned proximate the target, and a MRI image is obtained using the main magnet and the MTL coil. In another embodiment, the MRI coil is used for spectroscopy. MRI imaging and spectroscopy coils are formed using microstrip transmission line. These MTL coils have the advantageous property of good performance while occupying a relatively small space, thus allowing MTL coils to be used inside restricted areas more easily than some other prior art coils. In addition, the MTL coils are relatively simple to construct of inexpensive components and thus relatively inexpensive compared to other designs. Further, the MTL coils of the present invention can be readily formed in a wide variety of coil configurations, and used in a wide variety of ways. Further, while the MTL coils of the present invention work well at high field strengths and frequencies, they also work at low frequencies and in low field strengths as well.
U.S. Pat. No. 6,969,992 issued to Vaughan, et al. on Nov. 29, 2005, titled “Parallel transceiver for nuclear magnetic resonance system,” is incorporated herein by reference. This U.S. Pat. No. 6,969,992 describes an excitation and detection circuit having individually controllable elements for use with a multi-element radio frequency coil. Characteristics of the driving signal, including, for example, the phase, amplitude, frequency and timing, from each element of the circuit is separately controllable using small signals. Negative feedback for the driving signal associated with each coil element is derived from a receiver coupled to that coil element.
U.S. Pat. No. 7,710,117 issued to Vaughan, et al. on May 4, 2010, titled “Multi-current elements for magnetic resonance radio frequency coils,” is incorporated herein by reference. This U.S. Pat. No. 7,710,117 describes a current unit having two or more current paths that allow control of magnitude, phase, time, frequency and position of each of element in a radio frequency coil. For each current element, the current can be adjusted as to a phase angle, frequency and magnitude. Multiple current paths of a current unit can be used for targeting multiple spatial domains or strategic combinations of the fields generated/detected by combination of elements for targeting a single domain in magnitude, phase, time, space and frequency.
U.S. Pat. No. 7,514,926 issued to Adriany, et al. on Apr. 7, 2009, titled “Spatially reconfigurable magnetic resonance coil,” is incorporated herein by reference. This U.S. Pat. No. 7,514,926 discusses, among other things, a system and method for a coil having a plurality of resonant elements and an adjustable frame. A position of at least one resonant element can be adjusted relative to at least one other resonant element. A variable impedance is coupled to adjacent resonant elements and the impedance varies as a function of a separation distance. Cables are coupled to each resonant element and are gathered at a junction in a particular manner.
U.S. Pat. No. 7,598,739 issued to Vaughan, Jr., et al. on Oct. 6, 2009, titled “Radio frequency gradient, shim and parallel imaging coil,” is incorporated herein by reference. This U.S. Pat. No. 7,598,739 describes a plurality of linear current elements that are configured about a specimen to be imaged. A current in each current element is controlled independent of a current in other current elements to select a gradient and to provide radio frequency shimming. Each current element is driven by a separate channel of a transmitter and connected to a separate channel of a multi-channel receiver. The impedance, and therefore, the current, in each current element is controlled mechanically or electrically.
U.S. Pat. No. 7,633,293 issued to Olson, et al. on Dec. 15, 2009, titled “Radio frequency field localization for magnetic resonance,” is incorporated herein by reference. This U.S. Pat. No. 7,633,293 describes that technology for controlling non-uniformity in the B1 field includes selecting the phase, magnitude, frequency, time, or spatial relationship among various elements of a multi-channel excitation coil in order to control the radio frequency (RF) power emanating from the coil antenna elements. Non-uniformity can be used to steer a constructively interfering B1 field node to spatially correlate with an anatomic region of interest. A convex (quadratically constrained quadratic problem) formulation of the B1 localization problem can be used to select parameters for exciting the coil. Localization can be used in simulated Finite Difference Time Domain B1 field human head distributions and human head phantom measurement.
U.S. Patent Publication 2015/0323624 (application Ser. No. 14/619,051), filed Feb. 10, 2015 by Feinberg and Schillak titled “Device and method for loops-over-loops MRI coils” is incorporated by reference. Publication 2015/0323624 describes a method and apparatus for receiving (RX) radio-frequency (RF) signals suitable for MRI and/or MRS from MRI “coil loops” (antennae) that are overlapped and/or concentric, and each of which has a preamplifier and frequency-tuning circuitry and an impedance-matching circuitry, but wherein the loops optionally sized differently and/or located at different elevations (distances from the patient's tissue) in order to extract signal from otherwise cross-coupled coil loops and to improve signal-to-noise ratio (SNR) in images made from the received signal.
U.S. Patent Publication 2015/0196226 (application Ser. No. 14/548,276), filed Nov. 11, 2014 by Tramm et al. titled “Method and positionable patient-interface apparatus for an MRI system,” which claims priority to U.S. Provisional Patent Application No. 61/906,409 filed Nov. 19, 2013 titled “Method and apparatus for adjustable earpieces in an MRI system,” are each incorporated herein by reference in their entirety. Publication 2015/0196226 describes an apparatus and method for imaging a patient in an MRI system. This includes a frame, and at least one assembly that includes a patient-interface positioner connected to a reference position on the frame, a first lockable joint on the positioner; and a patient interface connected to a patient-proximal end of the positioner by a second joint, wherein the first patient-interface is moveably positioned to a selected pitch angle, a selected yaw angle, and a selected one of a plurality of distances relative to the reference position on the frame. The first lockable joint is configured to be tightened to yieldably hold the first patient-interface at the selected pitch and yaw angles, and at the selected one of the plurality of distances, relative to the reference position. Optionally a second substantially similar patient-interface and assembly are provided. The earpiece(s) optionally include audio transducer(s) and/or RF coil(s).
U.S. Pat. No. 9,160,295 to Waks et al. issued Oct. 13, 2015 with the title “Snap-on coaxial cable balun and method for trapping RF current on outside shield of coax after installation” and is incorporated herein by reference. Waks et al. describe an apparatus and method for a radially attachable RF trap attached from a side to a shielded RF cable. In some embodiments, the RF trap creates a high impedance on the outer shield of the RF cable at a frequency of RF signals carried on at least one inner conductor of the cable. In some embodiments, an RF-trap apparatus for blocking stray signals on a shielded RF cable that has a peripheral shield conductor and an inner conductor for carrying RF signals includes: a case; an LC circuit having a resonance frequency equal to RF signals carried on the inner conductor; projections that pierce and connect the LC circuit to the shield conductor; and an attachment device that holds the case to the cable with the LC circuit electrically connected to the shield conductor of the shielded RF cable.
There is a long-felt need for an improved body coil for an MRI system.